Working vehicle with transverse travel system

ABSTRACT

Front wheels ( 3 ) are attached to transmission devices ( 30 ) which are mounted to the vehicle body ( 2 ) to be rotatable around vertical axes ( 27 ), and rotating means ( 55 ) are provided between the side of the vehicle body ( 2 ) and the transmission devices ( 30 ), whereby the front wheels are steered to turn laterally at substantially right angles. An electric motor ( 40 ) is attached to the transmission device ( 30 ) to be located under the vertical axis ( 27 ). A case body ( 41 ) of the electric motor ( 40 ) is constructed by an outer case part ( 41 A) and a non-loaded side bracket ( 41 B), and a loaded side end portion of the outer case-part ( 41 A) is connected to the transmission device case body ( 31 ). The drive shaft ( 44 ) is rotatably supported by the non-loaded side bracket ( 41 B) at one end and by the transmission device case body ( 31 ) at the other end. A driving portion ( 34 ) provided at the other end side of the drive shaft ( 44 ) is operatively connected to an axle ( 28 ). As a result, a traveling drive device section can be constructed to be compact with assembling easiness.

TECHNICAL FIELD

The present invention relates to a working vehicle with a laterallytraveling system which can switch the working vehicle to lateraltraveling.

BACKGROUND ART

Conventionally, a self-propelled working truck which is found inJapanese Patent Unexamined Publication No. 2-306879 is proposed as aworking vehicle that can be switched to lateral traveling.

In this conventional construction, on a bottom face of a frame, twodrive wheels located on one diagonal line are provided via a directionturning shaft to be turnable, while two free idler wheels located on theother diagonal line are provided to be turnable, and both the drivewheels are operatively connected to each other by a direction changingconnecting part. The connecting part is constructed by turning leversprovided at a side of the direction turning shaft, a pair of rodsconnected to these turning levers at tip ends thereof, a hydrauliccylinder provided along the diagonal line on which both the drive wheelsare located, and a connecting fining which is provided at an extendablerod of this hydraulic cylinder and which connects inner ends of the pairof rods.

The drive wheels are attached to support fittings via a drive shaft, andthe support fitting is provided at the frame side via the directionturning shaft to be turnable. Further, a drive motor is provided at thesupport fitting, and a worm gear projected downward from the drive motoris meshed with a worm wheel of the drive shaft.

According to the conventional construction as described above, byextending and contracting the hydraulic cylinder, the rods are pushedand drawn along the diagonal line via the connecting fitting, wherebyboth the drive wheels can be turned in the opposite direction from eachother via the turning levers and the direction turning shaft. Therotation of the drive motor is transmitted to the worm gear, worm wheel,and the drive shaft, whereby the drive wheels can be rotationallydriven.

However in the above-described conventional construction, the drivemotor (traveling drive device) is provided to the support fittingoutside the turning axis, whereby the width of the drive wheel partwhich is turned becomes large, and therefore a large turning space hasto be secured, thus making the width (length) of the vehicle body largerand increasing the size of the entire body. The drive motor and the likeare independently constructed and thereafter installed, and thus thesize of the entire body is increased.

DISCLOSURE OF INVENTION

The present invention has its object to provide a working vehicle with alaterally traveling system which is of a type capable of steering drivetype front wheels to turn at substantially right angles in a lateraldirection while a traveling drive device section is constructed to becompact with excellent assembling easiness.

In order to attain the above object, a working vehicle with a laterallytraveling system of the present invention comprises a pair of left andright front wheels and a pair of left and right rear wheels mounted to avehicle body to be turnable by 90 degrees, the pair of left and rightfront wheels being attached to transmission devices mounted to thevehicle body to be rotatable around vertical axes, rotating meansprovided between the vehicle body and the transmission devices, and atravel-driving electric motor located under the vertical axis andattached to each of the transmission devices, and is characterized inthat each travel-driving electric motor has a case body comprising anouter case part and a non-loaded side bracket, the outer case parthaving a loaded side end portion connected to a case body of thetransmission device, one end of a drive shaft mounted with a rotor isrotatably supported by the non-loaded side bracket, and the other end isrotatably supported by the case body of the transmission device, and theother end of the drive shaft is provided with a driving portion of thetransmission device, which driving portion is operatively connected toan axle.

According to the invention with the above-described construction, theloaded side end portion of the outer case part in the case body of theelectric motor is connected to the case body of the transmission device,and the other end of the drive shaft is rotatably supported at the casebody of the transmission device, whereby the number of the components ofthe electric motor is reduced to be able to simplify the construction,and the section of the electric motor is improved in assembling easiness(mounting easiness), and can be constructed to be compact. In addition,the electric motor is located under the vertical axis, whereby the widthof the turning front wheel part, namely, the space for turning can bemade smaller, thus making it possible to reduce the width (length) ofthe vehicle body and downsize the entire body.

During normal traveling, the left and right front wheels and the leftand right rear wheels face the longitudinal direction. When switchingfrom the normal traveling to the laterally traveling, the rotating meansare operated first to rotate the transmission devices around thevertical axes, whereby the front wheels can be turned by 90 degrees(turned laterally at substantially right angles) with respect to thevehicle body. Here, the electric motors and the front wheels are locatedunder the vertical axes, whereby turning of the electric motors, thefront wheels and the like by 90 degrees is performed easily, smoothlyand compactly. After the drive type front wheels are turned laterally atsubstantially right angles (steered), the front wheels are driven in thenormal and reverse direction by the electric motors, whereby the workingvehicle can laterally travel either to the left or right.

The preferred embodiment in the working vehicle with the laterallytraveling system of the present invention is characterized in that themast is disposed at the front end side of the vehicle body, and forksare attached to the mast.

According to this embodiment, during normal traveling, the left andright front wheels and the left and right rear wheels face thelongitudinal direction, and by manipulating the lever for the lift, thefork is hoisted and lowered along the mast to perform a fork operationfor a predetermined period of time. While it is of the type whichenables a normal fork operation like this, it steers the drive typefront wheels to face laterally at substantially right angles to make itpossible to perform lateral traveling, and for example, an elongateobject can be transported easily via the forks.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an embodiment of the present invention, and is a partiallycutaway front view of a front wheel part of a working vehicle with alaterally traveling system;

FIG. 2 is a side view of the working vehicle with the same laterallytraveling system during normal traveling;

FIG. 3 is a side view of the front wheel part of the working vehiclewith the same laterally traveling system;

FIG. 4 is a schematic plan view of the working vehicle with the samelaterally traveling system during normal traveling; and

FIG. 5 is a schematic plan view of the working vehicle with the samelaterally traveling system during lateral traveling.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be explained below based onthe drawings. In FIG. 2, a fork lift 1 as an example of a workingvehicle is provided with a pair of left and right front wheels (drivewheels) 3 to a front portion of a vehicle body 2, a pair of left andright rear wheels (idler wheels) 4 to a rear portion thereof, and adriver's seat 5 above the front portion of the vehicle body 2. Avertically extendable mast 6 is disposed at the front end section of theaforementioned vehicle body 2 to be rotatable in a longitudinaldirection via a connecting shaft 7 in a vehicle width direction, a tiltcylinder 8 which effects the longitudinal rotation is provided betweenthe vehicle body 2 and the mast 6.

The mast 6 is constructed by a pair of left and right outer frames 9 ata side of the fork lift 1, and a pair of left and right inner frames 10descendable and ascendable by being guided by the outer frames 9, and alift cylinder 11 is provided between the outer frame 9 and the innerframe 10. A lift bracket 12 is provided to be capable of verticallymoving by being guided on the inner frame 10, and a pair of left andright forks 13 are attached to the lift bracket 12 via a pair ofvertical finger bars.

The driver's seat 5 is provided with a seat 15, a steering wheel 16located in front of the seat 15 and the like, and a head guard 19 isprovided thereabove via a front pipe 17 and a rear pipe 18 which areerected from the vehicle body 2. Further, a counterweight 20 is providedat a back of the seat 15 on the vehicle body 2.

In FIG. 1 to FIG. 4, the pair of left and right front wheels 3 and thepair of the left and right rear wheels 4 are mounted to the vehicle body2 so that they can be turned by 90 degrees (laterally turnable atsubstantially right angles). Namely, on both sides of the front portionof the vehicle body 2, vertical shafts 26 are provided to be rotatablearound vertical axes 27 via the respective bearings 25. A transmissiondevice case body 31 of a transmission device 30 is fixed at a lower endof the vertical axis 27, whereby the transmission device 30 is mountedto the vehicle body 2 to be rotatable around the vertical axis 27.

Here, the transmission device case body 31 is constructed by an innercase part 31A in an inverted L-shape, and an outer case part 31Battached to an outer face side of a vertical plate portion in this innercase part 31A, and a lateral plate portion of the inner case part 31A isfixed at a lower end of the vertical axis 26.

In the upper part of the transmission device case body 31, an oil seal32 can be placed in a penetrated portion formed in the inner case part31A, and a bearing 33 can be placed in a recessed portion formed in theouter case part 31B. A cylindrical driving gear (driving portion) 34 isrotatably supported by this bearing 33 via a cylindrical boss portion 34a.

Further, an axle 28 is rotatably provided via a wheel bearing 35 at theinner case part 31A in the lower part of the transmission device casebody 31, a driven gear (driven part) 36 is attached to the axle 28 to belocated inside the transmission device case body 31, a rim 3A of thefront wheel 3 is detachably attached to a part projected to the outsideof the transmission device case body 31 via a rotational flange 29 andthe like. The driving gear 34 and the driven gear 36 are operativelyconnected via a reduction gear mechanism 37 located inside thetransmission device case body 31. An example of the transmission device30 is constructed by the above-described components 31 to 37.

An electric motor 40 for traveling drive that is located below thevertical axis 27 is attached to the transmission device 30. Namely, acase body 41 of the electric motor 40 is constructed by a cylindricalouter case part 41A, and a non-loaded side bracket 41B which blocks anon-loaded side end portion (non-loaded side end) of the outer case part41A, and a loaded side end portion of the outer case part 41A isintegrated with a inner face side of the vertical plate portion of theinner case part 31A in the transmission device case body 31 by weldingor the like. As a result, the inner case part 31A of the transmissiondevice case body 31 is also used as a loaded side end bracket in theelectric motor 40.

A stator component such as a stator 42 is provided on an innercircumferential face of the outer case part 41A. The drive shaft 44mounted with a rotor 43 is placed inside the case body 41, and one endof the drive shaft 44 is rotatably supported at a bearing 45 in arecessed portion formed in the non-loaded side bracket 41B. The otherend of the drive shaft 44 is inserted through the driving gear 34 andconnected therewith.

As a result, the other end of the drive shaft 44 is rotatably supportedat the outer case part 31B of the transmission device case body 31 viathe cylindrical boss part 34 a of the driving gear 34 and the bearing33. The driving gear 34 provided at the other end of the drive shaft 44is operatively connected to the axle 28 via the reduction gear mechanism37 and the driven gear 36, whereby the pair of left and right frontwheels 3 are operatively connected to the respective drive shafts 44 ofthe electric motors 40. On this occasion, the front wheel 3 isconstructed to be located at an area immediately below the vertical axis27. An example of the electric motor 40 is constructed by theabove-described components 41 to 45 and the like.

A battery 50 is mounted on the vehicle body 2, and a controller 51 isattached to the battery 50. A cable 52 from the controller 51 isconnected to each of the electric motors 40.

Front wheel rotating means 55 for rotating the left and righttransmission devices 30 are provided. Namely, a turning cylinder 57 isprovided to be relatively rotatable between a link 56 provided at anupper end portion of the vertical shafts 26 and the vehicle body 2,whereby the left and right front wheels 3 are constructed to turn inopposite directions from each other to face laterally at substantiallyright angles, by extension movement of the turning cylinder 57. Anexample of the front wheel rotating means 55 is constructed by theabove-described components 56, 57 and the like.

In each of the pair of left and right rear wheels 4, a rim 4A isattached to a vertical plate portion in a turning member 60 via an axleand the like to be freely rotatable, and a lateral plate portion in theturning member 60 is attached to the vehicle body 2 to be rotatablearound a vertical axis 63 via a wheel bearing 61 and a vertical shaft62. In this situation, the rear wheel 4 is constructed to be located atan area immediately below the vertical axis 63.

Rear wheel rotating means 65 for rotating the left and right turningmembers 60 is provided. Namely, free ends of links 66 provided at upperend portions of the vertical shafts 62 are connected by a common link 67in a vehicle width direction, and a turning cylinder 68 is providedbetween a middle portion of the common link 67 and the vehicle body 2 tobe relatively rotatable. Accordingly, the left and right front wheels 3are constructed to be turned in the same direction to face laterally atsubstantially right angles by extension movement of the turning cylinder68. An example of the rear wheel rotating means 65 is constructed by theabove-described components 66 to 68 and the like.

An operation in the above-described embodiment will be explained below.

In the electric motor 40 section, a loaded side end portion of the outercase part 41A in the case body 41 is directly connected to the innercase part 31A of the transmission device case body 31, and the other endof the drive shaft 44 is rotatably supported by the outer case part 31Bof the transmission device case body 31, whereby the electric motor 40section can be constructed to be compact with excellent assemblingeasiness. In addition, the electric motor 40 is located under thevertical axis 27, whereby the width of the front wheel part which isturned, namely, the space for turning can be made smaller, and the widthof the vehicle body 2 (length) is decreased, thus making it possible toreduce the entire body in size.

The solid lines in FIG. 1 and FIG. 2, and FIG. 4 show situations at thetime of normal traveling. In these situations, the left and right frontwheels 3 and the left and right rear wheels 4 face the longitudinaldirection. The fork lift 1 like this can travel by operation of thesteering wheel 16 by the operator seated in the seat 15 of the driver'sseat 5. Namely, electric power of the battery 50 is controlled by thecontroller 51, and thereafter it is supplied to the electric motors 40via the cable 52, whereby the front wheels 3 are driven in a normal andreverse direction and the fork lift 1 can travel in a longitudinaldirection.

The lift cylinder 11 is operated by manipulating the lift lever, wherebythe fork 13 can be hoisted and lowered along the mast 6 via the liftbracket 12 and the like, thus making it possible to perform a forkoperation for a predetermined period of time. The tilt cylinder 8 isoperated by manipulating the tilt lever, whereby the mast 6 can berotated (tilted) around the connecting shaft 7, thus making it possibleto change the posture of the fork 13 via the lift bracket 12 and thelike.

When switching from the normal traveling as described above to lateraltraveling, the front wheel rotating means 55 and the rear wheel rotatingmeans 65 are operated by manipulating a lever type lateral mode switch(not shown) at first to tilt the lever.

Namely, both the turning cylinders 57 of the front wheel rotating means55 are synchronized and extended, and the transmission devices 30 arerotated in a reverse direction around the vertical axes 27 via the links56, whereby the front wheels 3 are turned by 90 degrees with respect tothe vehicle body 2 (laterally turned at substantially right angles) asshown by the phantom lines in FIG. 1 and FIG. 2, and FIG. 5.

Since the electric motors 40 and the front wheels 3 are located underthe vertical axes 27 in this situation, the electric motors 40, thefront wheels 3 and the like can be turned to 90 degrees easily,smoothly, and compactly.

Further, the turning cylinder 68 of the rear wheel rotating means 65 isextensively moved, and the turning members 60 are rotated in the samedirection around the vertical axes 63 via the common link 67 and thelinks 66, whereby the rear wheels 4 are turned by 90 degrees (laterallyturned at substantially right angles) with respect to the vehicle body 2as shown by the phantom lines in FIG. 1 and FIG. 2, and FIG. 5. Sincethe rear wheels 4 are located under the vertical axes 63, the rearwheels 4 and the like are made compact and can be turned by 90 degrees.

The turning of the front wheels 3 and the rear wheels 4 as describedabove, namely, turning the front wheels 3 and the rear wheels 4laterally at substantially right angles is sensed by the sensor, and anindicator lamp is lit, whereby a laterally traveling mode is madepossible. Accordingly, electric power of the battery 50 is controlled bythe controller 51 and thereafter it is supplied to both the electricmotors 40 via the cable 52, whereby the front wheels 3 are driven in thenormal and reverse direction, thus making it possible to make the forklift 1 travel laterally on the left and right. In this situation, thepair of left and right rear wheels 4 perform slave rotation.

As a result that lateral traveling can be performed as described above,for example, an elongate object can be transported easily via the fork13. Compensation of straightness in lateral traveling is facilitated bytilting the lever longitudinally to operate the turning cylinder 57slightly to perform fine tuning of the angles of the front wheels 3, orby operating the turning cylinder 68 slightly to perform fine tuning ofthe angles of the rear wheels 4.

In the above-described embodiment, a counter type fork lift 1 is shownas a working vehicle, but the same operation can be obtained if alarge-scale transporter, a loader, a side fork lift and the like areused as the working vehicle.

In the above-described embodiment, the cylindrical driving gear 34 isadopted as the drive part to make a type in which the drive shaft 44 islinked with the driving gear 34, but this may be a drive part of a typein which a driving gear is directly formed at the other end of the driveshaft 44. In this case, the number of the components of the transmissiondevice 30 can be reduced and the construction can be further simplified.

In the above-described embodiment, a type in which the pair of left andright rear wheels 4 are forcibly turned by the rear wheel rotating means65 is adopted, but a turning caster type which is turned by followingmay be adopted. Out of the pair of left and right rear wheels 4, one ofthe rear wheels 4 may be a steering type by a handle wheel, and theother one of the rear wheels 4 may be a turning caster type, and in thiscase, when switching to lateral traveling, the one of the rear wheels 4is forcibly turned by the cylinder and the like.

In the above-described embodiment, a type in which the pair of left andright front wheels 3 are independently rotated by the respective frontwheel rotating means 55 is shown, but this may be a type in which commonfront wheel rotating means for simultaneously rotating the pair of leftand right front wheels 3 is provided.

What is claimed is:
 1. A working vehicle with a laterally travelingsystem, comprising: a pair of transmission devices, each transmissiondevice having a case body and a driving portion; a pair of front wheelsand a pair of rear wheels all mounted to a vehicle body to be turnableat substantially right angles, the pair of front wheels each beingattached to one of said transmission devices mounted to the vehiclebody, each front wheel being rotatable around a vertical axis; rotatingmeans provided between the vehicle body and the transmission devices;and an electric motor located in the path of the vertical axis of eachfront wheel, each motor attached to one of the transmission devices,wherein: each electric motor has a motor case body comprising an outercase part and a non-loaded side bracket, the outer case part having aloaded side end portion connected to the case body of the transmissiondevice; one end of a drive shaft mounted with a rotor is rotatablysupported by the non-loaded side bracket and the other end of the driveshaft is rotatably supported by the case body of the transmissiondevice; and the other end of the drive shaft is provided with thedriving portion of the transmission device, the driving portion beingoperatively connected to an axle.
 2. The working vehicle with thelaterally traveling system according to claim 1, and further comprisinga mast disposed at a front end side of the vehicle body, and forksattached to the mast.